Refers to a
relationship between members of
different species from which they both
derive some form of advantage. The nature of the benefit for each species may be quite different, e.g. one
partner might gain protection from predators where as one gains a
nesting site or food source.
A good example of this is the relationship between humans and dogs, especially in prehistoric times. Both species gained a lot from this relationship and it is one we continue to cultivate to the present day.